Slippage devices are typically utilized in walk-behind lawnmowers in anticipation of the blade of the lawnmower striking or impacting a rigid object in the path of the blade. Conventional slippage devices typically utilize one or more slip plates to frictionally engage the blade, and the one or more slip plates are maintained in engagement with the blade by a bolt passing through the blade and the one or more slip plates and threadably engaging the end of the crankshaft in the lawnmower's engine. Typically, the bolt is torqued to a predetermined amount to allow slippage between the one or more slip plates and the blade if the blade were to impact a rigid object. Slippage devices like these help reduce the amount of damage done to the crankshaft during impacts with rigid objects.